The present invention relates to a method of producing intermetallic phases, e.g. alloys, from powdery ductile components that are mixed in a predetermined mixture ratio and are subsequently precompacted by cold pressing.
It is known to form intermetallic phases from alloys that essentially comprise titanium/aluminum, and that have a relatively good ductility at room temperature and a good creep strength, as a function of time, at high temperature; these known alloys can be cast and forged (German Offenlegungsschrift No. 30 24 645). Alloys of this type are used, for example, in jet drive plants as the starting material for the production of turbines, where high tensile strength, high ductility, high modulus of elasticity, high fatigue limit or creep strength, resistance to oxidation, and low density are of importance. Another application for such alloys is, for example, during the production of tools and motor components, where again the aforementioned properties are of importance.
Exhaustive tests have shown that a drawback of these heretofore known alloys is that they have a heterogeneous rather than a homogeneous structure, so that the expectations for the desired applications are not fulfilled. A further drawback of the previously known alloys of this type is their poor reproducibility with regard to the aforementioned properties, and also the fact that only very small quantities can be produced with the heretofore conventional methods of smelting.
Intermetallic phases, especially in the cast state, are brittle, so that they are customarily worked or shaped by hot process extrusion presses at very high temperatures. The tools that take part in this are stressed very greatly. An expensive furnace technology is required. Even laboratory furnaces that enable temperatures of up to 1350.degree. C. to be obtained are extremely expensive. A laboratory furnace for 1600.degree. C. costs approximately $10,000.00. An alloy such as TiAl is extruded, for example, at 1400.degree. C.
The forging process provides a heterogeneous structure, since the sample undergoes varying stress. In addition, it is possible to process only individual components during the forging. For greater quantities of samples, a greater expenditure is therefore necessary than during extrusion.
It is an object of the present invention to provide a method with which the aforementioned drawbacks are eliminated, and in particular any desired reproducibility of the required alloys can be achieved, whereby it is also possible to produce any desired quantity of the desired alloy in a single process phase.
This object, and other objects and advantages of the present invention, will appear more clearly from the following specification and examples.